Process and apparatus for producing dehydrated products



April 25, 1933. J. A. BURNER 1,905,263

PROCESS AND APPARATUS FOR PRODUCING DEHYDRATED PRODUCTS Filed Oct.- 2, 1930 29 Zalfaarnegse Parenteel` Apr.' 2 5, 1933 UNITED' STATES JAMES A. BURNER, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO AIR SYSTEMS IN-A PATENT -oFFlci-z CORPORATEROF MINNEAPOLIS, MINNESOTA1 A CORPORATION OF MINNESOTA PROCESS AND APPARATUS FOR PIR-ODUCING DEHYDRATED PRODUCTS Application led October 2, 1930. Serial No. 485,904.

This invention relates to processes and apparatus for dehydrating various products and particularly milk.

It is the mainobject of the present invenof parts hereinafter defined in the claims and described in the following specification,

Vmade in connection with the accompanying drawing, wherein like Vreference characters refer to the same or similar parts throughout the various views and, in which,-

Fig. 1 is a view taken chiey in vertical section but partly in side elevation through a complete apparatus embodying my in-y vention and used for carrying out my processes Fig. 2 is a vertical section-,taken on the line 2-2of Fig. 1, as indicated by the arrows; and

Fig. 3 is a plan view of the apparatus illustrated in Fig. 1.

The apparatus illustrated will be rst described and the processes wllthen be described in "connection with the apparatus shown. Although various liquid products y and other'products containing a high percentage of water or other liquids can be dehydrated, the apparatus and processes' will dried and condensed milk.

Referring to the drawing, there is illustrated an air conduit 4 leading into` the eye of a blower 5, operated by means of a. variable speed electric tn lotor 34 or any other suitable variable speed source of power and discharging into the rear end of a conduit be first described as used for producing 6. Within the conduit 6 there is mounted a heater 7 illustrated as being a radiator to which a heating medium may'- be supplied through a pipe 8 and may be discharged i through a pipe 9, the heating medium being heated from any source (not illustrated).

The conduit 6 is connected at its forward end to a truncated conical section 10 at the rear or receiving end of a horizontal drum 11. The conical section 10 is provided with helical vanes 12 or equivalent air whirling means to produce a whirl in the air in a certain direction charged into the drum 11' from the conduit v(i. A divider casin 13 of conical shape at its rear end an of curved partially spherical 4shape at its forward end is centrally supported within section 10 as by supportl 14, and mounted withf ywill of course be understood that the shaft 15 may be driven by any suitable but preferably variable speed source of power located either within or without divider casing 13. -The distributor 17 may be of any desired type to divide the milk, other liquid or other products. charged,to 'the nozzle into small particles and to produce a whirling action of the small particles of the same while moving the same forwardly in drum 11. The type of distributor 17 illustrated is probably asv simple as could be provided for successful use. The distributor 17 i1- lustrated has a central forwardly ,projecting divider portion 17a and from the peak of this divider portion, the forward surface of the distributor is concavely curved inwardly and toward the circumferential edge of the same. Adjacent the circumferential edge of the distributor there are provided a lurality of spaced pins 17b which .project orwardly and outwardly from the in the drawing as being a liquid supply conduitparticularlyadapted for supplying milk to the distributor 17 but any suitable conduit f for supplying either liquid or disintegrated partially solid products, such as potatoes,

i corn etc; may be substituted for the conduit 19l shown. The outlet 18 of the conduit 19 charges the product to be treated directly concavely curved surfaces thereof tothepins 1711.` As the distributor 17 will be rotated at high speed from the motor 15, the pins will act to break up the product into smallparticles and to produce a strong whirling action of these particles. The

motor shaft 16 ywill be so actuated that the nozzle 17 will rotate in an opposite di tion to the direction of whirl of the airp whirled in an op Aso 4tending downwardly from the duced 'by the air whirling means 12 and the' whirling particles although they are projected generally forwardly through the drum 11 'in the samegeneral direction as the air running therethrough, will be to the direction o `whirl of the air. The

vdrum 11 has at its forward endai second truncated conical section 20 connected to a conduit 21 which leads tangentially into a cyclone collector 22. The cyclone collector 22 has a cylindrical portion 22a adjacent its upper end into which tle conduit 21 extends and a funnel-shaped portion 225 excylindrical portion 22a and 'terminating in a collecting nozzle 22al at its lower end. Above the cylindrical portion 22a 'the c clone collector has an upwardly and centra ly flaring portion 22d to which a-conduit 23 is connected, the conduit 23 projecting downwardly in the collector and terminating at a point about level with the lower part of the cylindrical portion 22a. The conduit 23 .extends to a' second casing 24 forming a wetcondenser and preferably disposed slightly Vabove the cyclone collector 22 and of a shape very similar -to thejsaid collector. The casing 24 has a cylindrical portion a funnel-shaped portion 2411 and an upwardly and centrally flaring portion 24a shaped very similar to the portions 22a,

226 and 22d respectively'of the cyclone collector 22. The outletportion of the conduit 23 leading to the wet condenseris disposed substantially tangentially relative to the cylindrical portionl 24a of the same. Extending from adjacent the lower edge of the cylindrical portion 24a upwardly and through the upper end of the casing 24 is a large tubular conduit 25 which leads off to the atmosphere. A conduit 26 leading from any suitable source of liquid su ply such as a sourceof milk supply, exten s to a small liquid pump 27 and thence tc a heater 35 having pipes 36 and 27 connected thereto and supplylng and discharging a heating medium to the heater. The conduit 26`is preferably extended to a radiator or point adjacent the` lower end of the conical portion 245 thereof. The conduit 26 is connected to a vertical pipe 28 extending upwardly in the casing 24 to a point slight y below the inner end of the tubular conduit 25 and this pipe 28. is more horizontal pipes 29 which ,extend radially from the -pipe 28 to points between the cylildrical portion 24a and the tube 25. A plura ity to the vertical pipe 28 and to the en the pipes 29 .and these nozzles are so arrange that when a liquid product is sup plied 'through conduit 26 to the pipes 28 `and 29, all mner surfaces of the cas1ng^24 will be sprayed with the liquid. The lower end of the casing 24 is rovided with a small funnel-shaped detac able section 24d tonnected to two or of spray nozzles 30' are applied within which a 'funnel-shapedstrainer is ite direction relative` disposed in spaced relation from the walls thereof. A conduit 32 is connected to the lower end of the section 24d below the strainer 31 and runs to a rotary liquid' pum 33 and thence to a heater 38 havin con luits/ 39 and 40 respectivelyfor the a mission and discharge of a heating medium' other valve'43 is Y In using the apparatusfo'rA producing driedmilk and similar dried products del rived from liquid, the blower 5 or an equiv a lent air forcing means will be set in operation, heatingmediums jwill be supplied to the radiator 7 or an equivalent air heating means inthe conduit 6 and also to the heat- I The motor 15 will also be` ers 35 and 38. set in operation and the two -liquid pumps 27 and 33 will also be operated. Valve 42 A will be closed and valve 43 will be opened. Clhe liquid such as milk to be dried will be supplied throu liquid pump 2 and thence throughfthe heater 35 to the pipes 28 and 29." If milk is\ 120 being used, the milk will be sprayed fromthe nozzles under pressure from the pump 27 into the wet condenser-`24 and this milk Iwill be ins-warm condition due to its passage through the heater 35. The blower 5 willf force air at considerable pressure through the' conduit 6-and the radiator 7 `therein to heat the air, whereupon this air will travel through the drum 11 andthe cyclone .collech 4the conduit 26' to the v tor 22 and thence through the conduit 23 into .330.

the wet condenser 24. This air will take a spiral path within the wet condenser'24 due to the fact that the same is tangentially admitted to the wet condenser vand the air will swirl downwardly in the .wet condenser "24' to a point below the lower end of the ,tube 25. The milk sprayed from the nozzles 30 will come in contact with this air and a certain amount of the moisture from the denser and thence through the strainer 31 and detachable section 24d into the conduit 32. If it is desired to produce merely condensed milk, the valve 43 may be closed and the valve 42 opened, whereupon the milk in condensed condition may be drawn off through the extension conduit 41, If it is desired to produce dried milk, the valve 42 will be closed and the valve 43 opened, whereupon the milk with part of the moisture removed therefrom will pass through the conduit 32 to the pump 33 and thence to the heater 38 under pressure. The temperature of the milk will be raised by the heater 38 and the milk will be discharged through the conduit 19 and the discharge outlet 18 onto the distributor 17.

As the heated 4air is forced through the tube 6 into section 10 having the air whirling means '12 therein, the air will be-divided by the divider casing 13 into an annular stream and a strong whirl, for example, in a counter clockwise direction, as indicated by the arrows Fig. 2, will be produced in this air stream. The 'centrifugal force of this whirling stream of air will cause the same, as it is introduced into the drum '1 1, to seek the sides of the drum 11 while running forwardly in the drum. As the warm milk is disengaged from the outlet 18 of conduit 19 on to the distributor 17, the milk will be divided by the peak 17 a of the distributor as previously described, and broken up into small particles by the pins 176. The milk in finely divided condition will then be projected forwardly through the drum 1l in a whirling stream, the direction of whirl being opposite to the direction of whirl of the stream of air. In Vthe ldrawings Fig. 2, the inner arrow indicates that the direction of rotation of the ldistributor 17 is clockwise and, accordingly, the fine particles of milk will whirl in a clockwise direction and the body of milk will be centrally located in the drum 11 relative to the air passing therethrough. The air4 streamwill act to insulate the milk stream from the sides of the drum 11 and the milk will not strike the sides of the drum where it would otherwise lodge and burn due to the fact that the drum will be intensely heated by the hot air passing therethrough. The whirls of the air stream and the milk stream being oppsed will cause the milk to come into intlmate contact with the air and the hot air will quickly take up the moisture from the milk. The hot air will quickl reduce the milk to dried powdered orm and the -air which will now be quite moist, together with the dry powdered milk, i will be carried into the cyclone collector 22 through conduit 2l.

Attention should here be called to the fact that by varying the relative speed of the twoA motors 34 and 15 which Vis possible, due to the fact that these motors are variable speed motors, a stronger or weaker whirling action of the stream of air relative to the lstream of finely divided milkcan be obtained'l and the velocity of both the air stream and the milk stream can be varied. It may be desirable at times to increase the speed ofthe motor 34 relative 'to the speed of the motor 15 in-order that the air stream be desirable to increase the speed of the motor 15 relative to the motor 34, in order thatthe centrifugal force imparted to the milk particle4 stream may ,cause the milk particles to be carried more -closely adjacent the sides ofthe drum, thereby producing a slightly different drying action in the drum 11. It is possible, therefore, to vary the velocity of the stream of the air in the drum 11 and the stream of finely divided milk or other product that is being deaction between the two streams as they pass through the drum 11 without permitting the lroduct being dehydrated from scorching ue to'contact with the walls of the drum.

As the moist air and dry powderedmilk is .carried into the cyclone collector 22, the milk and air will whirl downwardly Within the' collector below the' lower edge of the conduit 23 and the dried powdered milk will drop into the funnel-shaped portion 22b ofthe collector, due largely to the fact that the pressure in the collector will be considerably Jlower than the pressure in the drum 11. Thev lhydrated to obtain the most efficient drying y tainers. At the time the milk andair enter fit? the cyclone collector 22, all offthe milk will be in driedpowdered form; The major portion of this milk will be collected in the coland dischargedV through the noz- However, a certain small pro rtion of the powdered milk will not op from the air in thev cyclone lcollector 22. The moist air and unseparated milkl in the collector will be carried out through the conduit 23 far removed from the point.

` where the powdered milk is collected in the lbottom'of the collector. Aecordin ly, the

air will not act toragain moisten t e4 dry, l collected milk and a very eilicient se arating action'betweenthe air and tli'e mi is obtained. The air with whatever milk there is, that has not been" collected in collector 22, will be carried through conduit 23 into the wet condenser 24. This air and milk will be introduced into the casing 24 in a streamV extendingA tangentially relative to the cylindrical portion 24a of the casingand 4 it will whirl downwardly through the casing to come in contact with the fresh milk discharged from sthe. ray nozzles 30, This fresh milk will absor all the dry milk that the air admitted to the wetcondenser 24 contains andiio milk will be carried out from the wet condenser into the atmos here through the tube- 25. The :position o the nozzles 30 connected to the horizontal pipes- 29 assures contact between the fresh and the powdered milk before the air can be discharged fromthe wet condenser. The d milk'l not collected in the collector 22 wi accordingly, be run through the' apparatus again with the fresh milk supplied thereto. Whatever heat there is that is left in the air as it is admitted ,to the wet vconv denser will be utilized to add heat to the milk in the w'et condenser. The air as it passes from the tube 25 will be completely or almost completely saturated with mois-- ture. l

It will be seen that none of the milk or' Vother liquid products that may be operated upon willbe wasted by use of thejpresent processes and apparatus.) It is found that whenmilk is dehydrated and the air from the blower 5 is'travelling at a velocity of one inch water glass pressure and the temperature of the air as'it is admitted to theV drum ii is between 25o and 300 F., time about% of the milk Pwill be collected in dried powdered form by the cllectorj 22.

The remaining mi is collected by thewetl condenser and again rim through the apparatus."- 'When partially solid products are dehydrated by tlgllpresent apparatus, the wet condenser 24 not be used or if used, the-pump 27 and heater 35 will not be set nf operation. vPreferably a slightly f'different typeof wet condenserswill be provided whenf' partially solid products are dehy,l

drated and diereiit'means used for supplying the products to the distributor 17 Practically any product having an evapo rative moisture contentcan be dehydrated by use ofmy processes-.and apparatus.

l It will, of course, be understood that various changs maybe made in the form, details, arrangement and proportions -of the various parts of theappa'ratus without departure'from thensco .of the present invention and that various chan s' may made `in the processes and in t e steps in the processes without departurefrom the sco e of the present invention.

atfis claimed isz- A 5 1. A dehydrating [apparatus having in combination, a blower, a drum into the rear- -end of which said blower leads, air whirling means in the rear end of said' drum, a divider centrally disposed ,in said drum relative to said air whirling means and in the path of the air to deflect the air and divide the same into an annular stream, a rotary distributork disposedahead of said divider Y in said drum, and facing toward'the for-` ward end of the drum, means for' supplying the product to be dehydrated to said' dis.

tibutor, means for rotating said distributor in a. direction generall tion that said air will1 be whirled by said air whirling means, and a collector con# -nected to the'forward end of-rsaid drum.

2. The process of producing a dehydrated opposite the direc'- product which'consists in passing air in a whirling stream through adrum and at the Sametime rotating a) body of liquid .product to break it up into a stream having 'a multiplicity of small particles moving under centrifugal force tangentially relativeto a central longitudinal axis and introducing said articles into said drum in inner concentric relation to saidair stream in such manner that the -product lparticle stream is projected in the same general longitudinal direction `through Athe drlim. as the air stream but the general centrifugal direction of the iiiovemeiitfofthe particle 'stream is opposed to the direction of whirl of the air stream thereby causing the air stream to act as an envelope to confine the hydrated particles of the product t'o prevent contact between the' same 'and the sides of the drum until the particles have been completely dehydrated. -v

3. A dehydrating apparatus havin-g in l combination a drum, means for introducing air in a whirling forwardly moving stream into therear end of said drum, a divider centrall disposed in said drum adjacent its rear en and deiecting the air to divide the same into an annular stream, and means for introducing a forwardly moving oppositely whirling stream of .small partlcles of the product to be deh drated into 4the drum ahead of said divi er, and a collector connected to the forward end of said` drum. In testimony whereof'I ailix my signature.

JAMES A. BURNER. 

